Ricoh B079, Service Manual

Page: 398 / 948

DEVELOPMENT
B079/B082 6-66 SM
6.9.7 TONER END RECOVERY
If the front door is opened and then closed while a toner near end/end condition
exists, the machine will attempt to recover. When the front door is closed, the toner
supply motor turns on to supply toner. The machine checks the TD sensor output 2
seconds after the main motor turns on (Vtp), and the sensor is checked again
every 1 second (Vtp
1
)
The machine detects the toner concentration using Vref, Vt (10), Vtp, and Vtp
1
. If
the toner concentration is still too low, the toner supply motor remains on for
another 10 seconds while the machine checks Vt. If toner concentration is judged
to be at the standard level, then the toner near end/end condition is cancelled and
K (toner supply coefficient) is reset. If toner concentration has not reached the
standard level, the toner supply motor rotates continuously until it does (maximum
motor on time is 16 seconds) and then it will switch off.
6.9.8 TONER SUPPLY WITH ABNORMAL SENSORS
The TD sensor is checked every copy. If the readings from the TD sensor become
abnormal during a copy job, the machine holds the GAIN factor constant (GAIN is
normally calculated from TD sensor readings) to allow toner supply to vary with
only pixel count for the rest of the copy job. Then at the end of the copy job, an SC
code is generated and the machine must be repaired.
The ID sensor is checked every 10 copies. If readings become abnormal, an SC
code is generated and the machine must be repaired. If this happens during a copy
job, Vref is not changed, the copy job is allowed to finish, and then the SC code is
generated.
If spare parts are not available, the technician can use SP2-208-1 to temporarily
put the machine in image pixel count mode. (
!
Chapter 5 Service Tables)